.. contents::


.. note:: To get more information about Geometry methods see `Geometry javadoc`_


Commons geometries methods
---------------------------

Interface Geometry: This interface is equivalent to the GM_Object specified in 
ISO 19107. A geometric object shall be a combination of a coordinate geometry 
and a coordinate reference system.
  
- area(): Return geometry area

- buffer(distance): Computes a buffer area around this geometry having the 
  given width

- centroid(): Return geometry centroid

- distance(geometry): Returns the minimum distance between this Geometry and 
  the specified geometry.

- getEnvelope(): Returns the minimum bounding box for this Geometry.

- getGeometryType(): Instance of the GeometryType associated to this geometry

- getDimension(): Returns the largest number n such that each direct position 
  in a geometric set can be associated with a subset that has the direct 
  position in its interior and is similar (isomorphic) to Rn, Euclidean n-space

Geometry types
---------------

Point
=====

This interface is equivalent to the GM_Point specified in 
ISO 19107. It is one of the basic data type for a geometric object consisting of 
one and only one point. They do not have volume, area, length, or any other 
higher-dimensional analogue.

- getX(): Returns the X coordinate

- getY(): Returns the Y coordinate

- getCoordinateAt(dimension): Gets the coordinate in a concrete dimension

  - param dimension: Dimension coordinate to get
  - type dimension: integer 
  - allowed values: 0=X, 1=Y, 2=Z

- setX(value): Sets the X coordinate

  - param value: Value of the dimension X
  - type value: double

- setY(value): Sets the Y coordinate

  - param value: Value of the dimension Y
  - type value: double

- setCoordinateAt(dimension, value): Sets a ordinate in a concrete dimension

  - param dimension: Dimension coordinate to set
  - type dimension: integer 
  - param value: Value of the dimension
  - type value: double


Line
=====

This interface is equivalent to the GM_OrientableCurve 
specified in ISO 19107. Curves are continuous, connected, and have a measurable 
length in terms of the coordinate system.

- addVertex(point): Adds a vertex to the curve

  - param point: Point to addLayer
  - type: Point 

- getNumVertices(): Gets the number of vertex of the curve

- getVertex(index): Gets a vertex 

  - param index: Geometry vertex index
  - type index: integer
    
Polygon
========

This interface is equivalent to the GM_Surface specified in 
ISO 19107. This is the basis for 2-dimensional geometry

- addVertex(point): Adds a vertex to the curve

  - param point: Point to addLayer
  - type: Point 

- getNumVertices(): Gets the number of vertex of the curve

- getVertex(index): Gets a vertex 

  - param index: Geometry vertex index
  - type index: integer

- getSurfaceAppearance(): Gets surface appearance

- setSurfaceAppearance(appearance): Sets surface appearance


Multigeometry
=============

This interface is equivalent to the GM_Aggregate specified in ISO 19107

- getPrimitiveAt(int i): Returns one of the Primitive's that is in a concrete 
  position.
  - param i: geometry position
  - type i: integer
- getPrimitivesNumber(): Returns the number of Primitive's that composes this 
  multi geometry.
  

Geometry util functions
=======================

- createGeometry(type[, subtype]): Create a new geometry with a concrete type 
  and subtype    

  - param type: geometry type
  - type type: integer
  - param subtype: (Optional) geometry subtype
  - type type: integer
  - return: geometry
  - rtype: Geometry

- createPoint([x][, y][, subtype]): Create a new point with a subtype dimensions 
  and sets the value for 'X' and 'Y' coordinates. If is used without parameters 
  will return new Point2D with (0,0) coordinates

  - param x:(Optional) X coordinate value
  - type x: double
  - param y:(Optional) Y coordinate value
  - type y: double
  - param subtype: (Optional) geometry dimensions
  - type: integer    
  - return: Point
  - rtype: Point  

- createMultiPoint(points[, subtype]): Create a new multipoint with a 
  subtype from a list values of X and Y like ([x1, y1], [x2, y2], ...., [xn, yn])

  - param points: list of tuples with X and Y values
  - type points: list
  - param subtype: (Optional) geometry dimensions
  - type: integer
  - return: multipoint
  - rtype: multipoint

  
.. _`Geometry javadoc`: http://devel.gvsig.org/sites/org.gvsig.fmap.geometry/2.0-SNAPSHOT/gvsig-base-library-pom/org.gvsig.fmap.geometry/api/org/gvsig/fmap/geom/Geometry.html